520 research outputs found
Measurements of the lead-hydrocarbon cross section ratio for charged-current neutrino interactions
Studying the neutrino cross sections of various materials is of great importance in the analysis of data from neutrino oscillation experiments, as well as interesting in its own right. We have examined the charged-current muon neutrino cross section ratio between lead and scintillator, with our lead target being in the MINERvA electromagnetic calorimeter. This choice has allowed us to obtain usable efficiencies out to much larger muon angles than was feasible from the upstream targets. Comparing the cross section ratio in the data and Monte Carlo, we have found that the ratios agree reasonably well as a function of neutrino energy, but with a distinct excess at low energies. However, there are significant differences between data and Monte Carlo at low and high values of Bjorken x
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Sex-specific processing of social cues in the medial amygdala
Animal–animal recognition within, and across species, is essential for predator avoidance and social interactions. Despite its essential role in orchestrating responses to animal cues, basic principles of information processing by the vomeronasal system are still unknown. The medial amygdala (MeA) occupies a central position in the vomeronasal pathway, upstream of hypothalamic centers dedicated to defensive and social responses. We have characterized sensory responses in the mouse MeA and uncovered emergent properties that shed new light onto the transformation of vomeronasal information into sex- and species-specific responses. In particular, we show that the MeA displays a degree of stimulus selectivity and a striking sexually dimorphic sensory representation that are not observed in the upstream relay of the accessory olfactory bulb (AOB). Furthermore, our results demonstrate that the development of sexually dimorphic circuits in the MeA requires steroid signaling near the time of puberty to organize the functional representation of sensory stimuli. DOI: http://dx.doi.org/10.7554/eLife.02743.00
Establishing Students’ Abilities to Reason with Relationships in the Context of Cellular Respiration
This study aims to establish the level at which University of Nebraska-Lincoln students reason with simple relationships in the context of cellular respiration at the levels of glycolysis, Krebs cycle, and electron transport chain. These processes are component processes of cellular respiration and each has multiple inputs and outputs. 633 student consented for this study, from which 18 student models were randomly selected, processed, and analyzed. Classroom observations were used to determine structures and relationships that were inputs and outputs to the three processes. In their models, students did not include different numbers of input or outputs when describing glycolysis, Krebs cycle and the electron transport On average, students had about one input and more than one output per process. The correctness was high for all three processes, however, relationships associated with Krebs cycle were significantly lower than relationships associated with ETC. Relationships associated with glycolysis were intermediate in quality. It was concluded that student\u27s still have a limited understanding of all processes, despite high correctness, because only one input and output for each process was included when three to four should be expected. Students must develop their system thinking skills to comprehend the smaller components at a high level, before they can consider the entire system. Current research suggests that computational modeling is one approach the University can implement as an activity to develop students\u27 system thinking skills
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Galanin neurons in the medial preoptic area govern parental behavior
Mice display robust, stereotyped behaviors toward pups: virgin males typically attack pups, while virgin females and sexually experienced males and females display parental care. We show here that virgin males genetically impaired in vomeronasal sensing do not attack pups and are parental. Further, we uncover a subset of galanin-expressing neurons in the medial preoptic area (MPOA) that are specifically activated during male and female parenting, and a different subpopulation activated during mating. Genetic ablation of MPOA galanin neurons results in dramatic impairment of parental responses in males and females and affects male mating. Optogenetic activation of these neurons in virgin males suppresses inter-male and pup-directed aggression and induces pup grooming. Thus, MPOA galanin neurons emerge as an essential regulatory node of male and female parenting behavior and other social responses. These results provide an entry point to a circuit-level dissection of parental behavior and its modulation by social experience
Mycophenolate pharmacokinetics and pharmacodynamics in belatacept treated renal allograft recipients – a pilot study
<p>Abstract</p> <p>Background</p> <p>Mycophenolic acid (MPA) is widely used as part of immunosuppressive regimens following allograft transplantation. The large pharmacokinetic (PK) and pharmacodynamic (PD) variability and narrow therapeutic range of MPA provide a potential for therapeutic drug monitoring. The objective of this pilot study was to investigate the MPA PK and PD relation in combination with belatacept (2<sup>nd </sup>generation CTLA4-Ig) or cyclosporine (CsA).</p> <p>Methods</p> <p>Seven renal allograft recipients were randomized to either belatacept (n = 4) or cyclosporine (n = 3) based immunosuppression. Samples for MPA PK and PD evaluations were collected predose and at 1, 2 and 13 weeks posttransplant. Plasma concentrations of MPA were determined by HPLC-UV. Activity of inosine monophosphate dehydrogenase (IMPDH) and the expressions of two <it>IMPDH </it>isoforms were measured in CD4+ cells by HPLC-UV and real-time reverse-transcription PCR, respectively. Subsets of T cells were characterized by flow cytometry.</p> <p>Results</p> <p>The MPA exposure tended to be higher among belatacept patients than in CsA patients at week 1 (P = 0.057). Further, MPA concentrations (AUC<sub>0–9 h </sub>and C<sub>0</sub>) increased with time in both groups and were higher at week 13 than at week 2 (P = 0.031, n = 6). In contrast to the postdose reductions of IMPDH activity observed early posttransplant, IMPDH activity within both treatment groups was elevated throughout the dosing interval at week 13. Transient postdose increments were also observed for <it>IMPDH1 </it>expression, starting at week 1. Higher MPA exposure was associated with larger elevations of <it>IMPDH1 </it>(r = 0.81, P = 0.023, n = 7 for MPA and <it>IMPDH1 </it>AUC<sub>0–9 h </sub>at week 1). The maximum <it>IMPDH1 </it>expression was 52 (13–177)% higher at week 13 compared to week 1 (P = 0.031, n = 6). One patient showed lower MPA exposure with time and did neither display elevations of IMPDH activity nor <it>IMPDH1 </it>expression. No difference was observed in T cell subsets between treatment groups.</p> <p>Conclusion</p> <p>The significant influence of MPA on <it>IMPDH1 </it>expression, possibly mediated through reduced guanine nucleotide levels, could explain the elevations of IMPDH activity within dosing intervals at week 13. The present regulation of IMPDH in CD4+ cells should be considered when interpreting measurements of IMPDH inhibition.</p
Simulation of the transit-time optical stochastic cooling process in the Cornell Electron Storage Ring
In preparation for a demonstration of optical stochastic cooling in the
Cornell Electron Storage Ring (CESR) we have developed a particle tracking
simulation to study the relevant beam dynamics. Optical radiation emitted in
the pickup undulator gives a momentum kick to that same particle in the kicker
undulator. The optics of the electron bypass from pickup to kicker couples
betatron amplitude and momentum offset to path length so that the momentum kick
reduces emittance and momentum spread. Nearby electrons contribute an
incoherent noise. Layout of the bypass line is presented that accommodates
optics with a range of transverse and longitudinal cooling parameters. The
simulation is used to determine cooling rates and their dependence on bunch and
lattice parameters for bypass optics with distinct emittance and momentum
acceptance
Selenomethionine and methyl selenocysteine: multiple-dose pharmacokinetics in selenium-replete men
According to the Nutritional Prevention of Cancer (NPC) trial, a selenized yeast supplement containing selenium, 200 mcg/day, decreased the incidence of total cancer, cancers of the prostate, colon and lung, and cancer mortality. The active agent in the selenized yeast supplement was assumed to be selenomethionine (SEMET), although the supplement had not been well speciated. The SELECT study, largely motivated by the NPC trial, enrolling nearly 40 times as many subjects, showed unequivocally that selenium 200 mcg/day, with selenium in the form of SEMET, does not protect selenium-replete men against prostate or other major cancer. The agent tested by SELECT, pure SEMET, could have been different from the selenized yeast tested in NPC. One of the selenium forms suspected of having chemopreventive effects, and which may have been present in the NPC agent, is methyl selenocysteine (MSC). This study, with 29 selenium-replete patients enrolled in a randomized, double-blind trial, compared the multiple-dose toxicity, pharmacokinetics and pharmacodynamics of MSC and SEMET. Patients were on trial for 84 days. No toxicity was observed. Although SEMET supplementation increased blood selenium concentration more than MSC did, neither form had a more than minimal impact on the two major selenoproteins: selenoprotein P(SEPP1) and glutathione peroxidase(GPX)
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